An endocutter is a surgical tool that staples and cuts tissue to transect that tissue while leaving the cut ends hemostatic. An endocutter is small enough in diameter for use in minimally invasive surgery, where access to a surgical site is obtained through a trocar, port, or small incision in the body. A linear cutter is a larger version of an endocutter, and is used to transect portions of the gastrointestinal tract. A typical endocutter receives at its distal end a disposable single-use cartridge with several rows of staples, and includes an anvil opposed to the cartridge. During actuation of an endocutter, the cartridge fires all of the staples that it holds. In order to deploy more staples, the endocutter must be moved away from the surgical site and removed from the patient, after which the old cartridge is exchanged for a new cartridge. The endocutter is then reinserted into the patient. However, it can be difficult and/or time-consuming to located the surgical site after reinsertion. Further, the process of removing the endocutter from the patient after each use, replacing the cartridge, and then finding the surgical site again is tedious, inconvenient and time-consuming, particularly where a surgical procedure requires multiple uses of the endocutter.
In order to overcome these difficulties, Cardica, Inc. of Redwood City, Calif. has developed a true multi-fire endocutter that is capable of firing multiple times without the need to utilize single-use-cartridges. That endocutter is described in, for example, application Ser. No. 12/263,171, filed Oct. 31, 2008 (the “Endocutter Application”), which is hereby incorporated herein by reference in its entirety. Referring to FIG. 1, the Endocutter Application, among other items, discloses a feeder belt 2 to which a plurality of staples 4 are frangibly attached. The feeder belt 2 bends around a pulley 6 at its distal end. Each end of the feeder belt 2 is connected to a different rigid, toothed rack 8, and each rack engages a gear 10. The racks 8 are rigid, and as a result advancement of one rack 8 causes the gear 10 to rotate and thereby move the other rack 8 in the opposite direction. The gear 10 is located in a shaft 12 of the tool, between the handle and a distal end of the shaft. Because the racks 8 are rigid, the linear travel of the racks 8 is limited by the length of the shaft 12 and of the handle connected to the shaft. Consequently, the number of firings that can be made by the tool is limited by the linear distance that the racks 8 can travel within the shaft 12 and structure connected to the shaft 12.
The use of the same reference symbols in different figures indicates similar or identical items.